1. Technical Field
The present invention relates to a physical quantity detection device, a physical quantity detector, and an electronic device.
2. Related Art
Hitherto, physical quantity detection devices (for example, acceleration sensors) making use of a physical quantity detection element such as a vibrator (resonator) have become known. When a resonance frequency of the physical quantity detection element changes with the action of force in the detection axis direction, such physical quantity detection devices are configured to detect force (acceleration) applied to the physical quantity detection device due to a change in the resonance frequency.
In such a physical quantity detection device, for example, a mass portion is provided in a movable portion which is displaced when acceleration is applied, and detection sensitivity of the acceleration is increased (see JP-A-2011-169671).
However, in a technique disclosed in JP-A-2011-169671, since thermal expansion coefficients of the movable portion and the mass portion are different from each other, stress has sometimes occurred in the movable portion due to the difference between both thermal expansion coefficients. Such stress has sometimes been transmitted to the physical quantity detection element. As a result, detection sensitivity of the physical quantity detection device has sometimes decreased due to a fluctuation in the resonance frequency of the physical quantity detection element by the transmitted stress.